The invention relates to methods of machining grooves in shafts and other rotary workpieces, and more particularly to improvements in methods of machining elongated (particularly axially parallel) grooves in the peripheries of shafts and the like.
If a shaft is to be provided with an axially parallel groove in a CNC turning machine wherein the tool is rotated, the machine employs a milling tool whose diameter matches the desired width of the groove. The tool is moved in the radial and axial directions of the workpiece, and the groove is machined in a single operation. A drawback of such methods of machining grooves is that the tool must be discarded as soon as it has undergone a certain amount of wear, i.e., the tool cannot be subjected to a grinding and/or other finishing treatment preparatory to renewed use. Therefore, the machining of grooves in CNC turning machines is too expensive for a large number of purposes.
Grooves, channels, recesses and similar cavities are also machined in milling machines wherein the removal of material is effected in several steps by a milling tool whose diameter is less than the desired width of the groove. When the first material removing step is completed, the milling tool is moved sideways prior to renewed penetration into the material of the workpiece. Reference may be had to German Auslegeschrift No. 11 53 966. Such sidewise movement of the tool is not possible in a turning machine without special (expensive) equipment.